package com.gitee.magic.framework.base.utils;

import java.net.Inet4Address;
import java.net.InetAddress;
import java.net.InterfaceAddress;
import java.net.NetworkInterface;
import java.net.SocketException;
import java.net.UnknownHostException;
import java.util.Enumeration;

import com.gitee.magic.core.exception.ApplicationException;

import jakarta.servlet.http.HttpServletRequest;

/**
 * @author start
 */
public class IpUtils {
	
	/**
	 * 直接根据第一个网卡地址作为其内网ipv4地址，避免返回 127.0.0.1
	 *
	 * @return
	 */
	public static String getLocalIpByNetcard() {
		try {
			for (Enumeration<NetworkInterface> e = NetworkInterface.getNetworkInterfaces(); e.hasMoreElements();) {
				NetworkInterface item = e.nextElement();
				for (InterfaceAddress address : item.getInterfaceAddresses()) {
					if (item.isLoopback() || !item.isUp()) {
						continue;
					}
					if (address.getAddress() instanceof Inet4Address) {
						Inet4Address inet4Address = (Inet4Address) address.getAddress();
						return inet4Address.getHostAddress();
					}
				}
			}
		} catch (SocketException e) {
			throw new ApplicationException(e);
		}
		return getLocalIp();
	}

	public static String getLocalIp() {
		try {
			return InetAddress.getLocalHost().getHostAddress();
		} catch (UnknownHostException e) {
			throw new ApplicationException(e);
		}
	}
	
	/**
	 * 获取用户真实IP地址，不使用request.getRemoteAddr();的原因是有可能用户使用了代理软件方式避免真实IP地址,
	 * 
	 * 可是，如果通过了多级反向代理的话，X-Forwarded-For的值并不止一个，而是一串IP值，究竟哪个才是真正的用户端的真实IP呢？
	 * 答案是取X-Forwarded-For中第一个非unknown的有效IP字符串。
	 * 
	 * 如：X-Forwarded-For：192.168.1.110, 192.168.1.120, 192.168.1.130, 192.168.1.100
	 * 
	 * 用户真实IP为： 192.168.1.110
	 */
	public static String getRequestIp(HttpServletRequest request) {
		String unknown="unknown";
		String ip = request.getHeader("x-forwarded-for");
		if (ip == null || ip.length() == 0 || unknown.equalsIgnoreCase(ip)) {
			ip = request.getHeader("Proxy-Client-IP");
		}
		if (ip == null || ip.length() == 0 || unknown.equalsIgnoreCase(ip)) {
			ip = request.getHeader("WL-Proxy-Client-IP");
		}
		if (ip == null || ip.length() == 0 || unknown.equalsIgnoreCase(ip)) {
			ip = request.getHeader("HTTP_CLIENT_IP");
		}
		if (ip == null || ip.length() == 0 || unknown.equalsIgnoreCase(ip)) {
			ip = request.getHeader("HTTP_X_FORWARDED_FOR");
		}
		if (ip == null || ip.length() == 0 || unknown.equalsIgnoreCase(ip)) {
			ip = request.getRemoteAddr();
		}
		return ip;
	}
	
}
